The invention relates generally to self-loading and unloading wheeled vehicles, and more particularly to vehicles adapted for self-loading and unloading of rolled materials such as carpet.
The handling of large rolls of carpet presents a difficult problem. Such rolls are bulky and very heavy, weighing 1000 to 1500 pounds each. Consequently, manual handling of carpet rolls is clearly undesirable. Carpet rolls must also be handled gently to avod damaging or soiling them.
In carpet warehouses, rolls of carpet are usually handled by means of a forklift. However, forklifts are often difficult to maneuver in tight spaces inside a carpet warehouse. Their use frequently results in damage either to the rolls of carpet being handled or to other nearby rolls. To exercise proper care in using a forklift in the warehouse can be very time consuming, resulting in an undesireable tradeoff between labor costs and damaged carpet. Moreover, forklifts are very expensive both to purchase and to operate.
As a result, several carpet handling devices have been proposed in U.S. Pat. Nos. 2,656,050 to Best et al. and 3,750,811 to Anderson et al. Best et al. propose a four-wheeled dolly having a roller-type cradle for the carpet roll which is particularly adapted for rolling and unrolling the carpet while positioned on the dolly. Such a device is unable to self-load a carpet positioned either at floor level, in the bed of a truck, or on a pile of carpet rolls. Hence, its utility is quite limited.
Anderson et al. propose a wheeled carpet roll unloading and transporting frame which is designed to straddle a roll of carpet lengthwise. A rod is inserted through the central opening in the roll of carpet and the ends of the rod are connected to cables extending downwardly from the frame. A winch is operable to wind and unwind the cables to raise and lower the carpet. One of the cables can also be used for unloading a roll of carpeting from a truck. However, this frame assembly is very difficult to maneuver inside a warehouse, particularly when carrying a carpet roll. It also does not appear to be usable to load a carpet roll into a truck.
A different set of problems arises when transporting carpet rolls to a remote building site and unloading them. There is usually no forklift on site. Nor can a forklift be easily transported to the many sites to which carpet may be delivered. The apparatus proposed by Anderson et al. has the same lack of portability as a forklift, while the apparatus proposed by Best et al. is unable to unload a carpet from a truck. Consequently, when delivering carpet to a remote building site, it is necessary to provide sufficient manpower to manually handle the carpet rolls. Since it would be very expensive to provide sufficient manpower on a delivery truck, carpet is usually delivered by a lone driver. The driver relies upon being able to get help in unloading the carpet when he arrives at the building site. If help is not available, the driver frequently must abort the delivery and return at another time, greatly increasing delivery costs.
As a solution to this problem, Anderson et al. propose, in U.S. Pat. No. 3,971,484, a truck-mounted carpet roll loading and unloading system which is built into the roof of a covered delivery truck. This system includes an electric winch and cable assembly for pulling a carpet into and out of the back of the truck. However, this system is limited to use in the immediate vicinity of the truck. If the carpet roll must be transported some distance between the truck and the place where it is to be deposited, this system is useless.
Although not designed for handling carpet rolls, other self-loading vehicles have been proposed.
U.S. Pat. No. 1,708,854 to Stahlhut, proposes a truck for handling rolled sheet steel. It includes a winch and cable system that operates to pull a roll of sheet steel lengthwise onto a conveyor platform. The device has conveyor rollers on the platform, but does not appear to include means for driving the rollers. Also lacking are means for driving the wheels of the device. Hence, this device does not appear to be usable for loading or unloading carpet rolls in a variety of situations. In addition, it does not appear to be usable for transporting carpet rolls, particularly across uneven or soft terrain. It also does not appear to be particularly portable.
U.S. Pat. No. 2,572,945 to Quesnoit, proposes a dolly having a platform tiltably mounted above a pair of wheels. The platform includes a separate, wheeled ramp for supporting an object to be loaded so that it can be rolled onto the platform. A winch positioned at one end of the platform has a chain which connects to an object to be loaded for pulling the object onto the platform from the opposite end. The platform itself lacks a conveyor which is drivable to assist the winch in pulling the roll of carpet onto the dolly or in unloading the carpet. Hence, this device does not appear to be useful for handling rolls of carpet.
Several specialized, four-wheeled, non-tiltable self-loading vehicles have been proposed. U.S. Pat. No. 26,421 to Francher proposes a stone loading wagon. U.S. Pat. No. 1,597,592 to Galloway proposes a truck especially adapted for carrying large plate glass panels and the like. U.S. Pat. No. 2,659,504 to Kranawetvogel et al., proposes a trailer adapted for loading and transporting, in piggy-back fashion, wheeled containers. However, none of these designs appear to be useful for handling rolls of carpet.
Accordingly, there remains a need for a self-loading and unloading apparatus suitable for handling large rolls of carpet both in a carpet warehouse and at remote sites.